Setaria pumila

About

Setaria pumila is a species of grass known by many common names, including yellow foxtail, yellow bristle-grass, pigeon grass, and cattail grass. It is native to Europe, but it is known throughout the world as a common weed. It grows in lawns, sidewalks, roadsides, cultivated fields, and many other places. This annual grass grows 20 centimetres to well over 1 metre in height, its mostly hairless stems ranging from green to purple-tinged in color. The leaf blades are sparsely to barely covered in hair, twisting, and up to 30 centimetres long. The inflorescence is a stiff, cylindrical bundle of spikelets 2 to 15 centimetres long with short, blunt bristles. The panicle may appear yellow or yellow-tinged.

Summary from Wikipedia